Sweet dairy whey is a co-product from cheese production. Cheese is produced from cows' milk which in dry form includes; lactose (about 38%), fat (about 26%), protein (about 26%), mineral ash (about 6%) and moisture (about 4%). The cheese making process extracts most of the fat and a selected portion of the protein out of the milk. What remains of the cows' milk is referred to as sweet dairy whey and it includes much of the desirable (nutritious) ingredients available in cows' milk.
Sweet dairy whey is well recognized as having good nutritional value but also having a texture and flavor that is repulsive as a separate food or drink. As a result, historically sweet dairy whey was considered a waste product and because it is about 90% of the original milk volume, it created a substantial disposal problem. Over time cheese producers learned to dry the sweet dairy whey and include the nutritional dry sweet dairy whey as an ingredient for animal foods. More recently, the dry sweet dairy whey has been converted into a dairy drink intended to resemble the taste and texture of milk and is referred to as imitation milk.
The principal task of the imitation milk producer was to get rid of the repulsive taste of the sweet dairy whey. Essentially this was done by producing a mixture of sweet dairy whey and "other" ingredients which typically amounted to about 50% non-processed sweet dairy whey and 50% "other" ingredients. Such mixtures are represented by the formulas found in U.S. Pat. Nos. 4,337,278, 4,397,927 and 4,446,164.
Whereas the patents overtly recognize that they do not know why the particular mixtures get rid of the bad taste, it is theorized that the bad taste is simply covered up in the mixture, first by diluting the mixture to a content of about one-half sweet dairy whey and adding in salts and flavoring.
A major reason for using the non-processed sweet dairy whey in the imitation mixture was to retain the milk taste. Thus, the use of sweet dairy whey was considered necessary and the combination of other ingredients, besides having to cover up the bad taste, had to be balanced to retain or enhance the milk taste. These factors resulted in the development of rather complex formulations as will be noted from the cited patents.